fix: fallback to GtkStatusIcon when app indicator is not supported (#36815)

* chore: get ready for multi backend tray

* fix: fallback to GtkStatusIcon when app indicator is not supported

* chore: use smart pointers

shell/browser/ui/gtk/menu_gtk.cc

@@ -0,0 +1,70 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "shell/browser/ui/gtk/menu_gtk.h"
+
+#include <gtk/gtk.h>
+
+#include "shell/browser/ui/gtk/menu_util.h"
+#include "ui/base/models/menu_model.h"
+
+namespace electron {
+
+namespace gtkui {
+
+MenuGtk::MenuGtk(ui::MenuModel* model)
+    : menu_model_(model), gtk_menu_(TakeGObject(gtk_menu_new())) {
+  if (menu_model_) {
+    BuildSubmenuFromModel(menu_model_, gtk_menu_,
+                          G_CALLBACK(OnMenuItemActivatedThunk),
+                          &block_activation_, this);
+    Refresh();
+  }
+}
+
+MenuGtk::~MenuGtk() {
+  gtk_widget_destroy(gtk_menu_);
+}
+
+void MenuGtk::Refresh() {
+  gtk_container_foreach(GTK_CONTAINER(gtk_menu_.get()), SetMenuItemInfo,
+                        &block_activation_);
+}
+
+GtkMenu* MenuGtk::GetGtkMenu() {
+  return GTK_MENU(gtk_menu_.get());
+}
+
+void MenuGtk::OnMenuItemActivated(GtkWidget* menu_item) {
+  if (block_activation_)
+    return;
+
+  ui::MenuModel* model = ModelForMenuItem(GTK_MENU_ITEM(menu_item));
+  if (!model) {
+    // There won't be a model for "native" submenus like the "Input Methods"
+    // context menu. We don't need to handle activation messages for submenus
+    // anyway, so we can just return here.
+    DCHECK(gtk_menu_item_get_submenu(GTK_MENU_ITEM(menu_item)));
+    return;
+  }
+
+  // The activate signal is sent to radio items as they get deselected;
+  // ignore it in this case.
+  if (GTK_IS_RADIO_MENU_ITEM(menu_item) &&
+      !gtk_check_menu_item_get_active(GTK_CHECK_MENU_ITEM(menu_item))) {
+    return;
+  }
+
+  int id;
+  if (!GetMenuItemID(menu_item, &id))
+    return;
+
+  // The menu item can still be activated by hotkeys even if it is disabled.
+  if (model->IsEnabledAt(id))
+    ExecuteCommand(model, id);
+}
+
+}  // namespace gtkui
+
+}  // namespace electron